This invention relates to systems for the protection of secure areas, and to intruder detection systems. Specifically, it relates to an intruder detecting sensing device that can be integrated into a physical deterrent barrier and that is adapted to surveillance of the air space over the deterrent barrier.
It is often necessary to protect equipment and secure areas from unauthorized, unwanted and somtimes hostile personnel and vehicles. Such protection conventionally includes fencing that encompasses the area or equipment to be protected. Intruder detection systems are also used in conjunction with fences or other physical deterrent barriers to enable responsible personnel to monitor the premises and to take appropriate action in response to detected intrusions. One well known state-of-the-art intrusion detection system utilizes radar ranging principles. This type of system is implemented by means of a leaky transmission line that encompasses the secure area. Violation by an intruder of the r.f. field that radiates from the leaky transmission line results in reflections which can be processed in a known manner to identify and locate any given intrusion event.
Although both physical deterrent barriers and state-of-the-art intruder detection systems are reasonably effective individually they have never been fully integrated in order to improve efficiency and increase monitoring capability and protection of the secure area. Furthermore, the air space over the physical deterrent barrier in these systems has never been monitored. This unprotected area thus introduces a possible security breach. There currently exists, therefore, the need for secure area protection systems that provide physical deterrent barriers having integrated intruder sensors for monitoring the air space over the barrier. The present invention is directed toward satisfying that need. It is proposed that this be accomplished by providing an integrated physical barrier-monitor system that acts as both intruder deterrent and intruder detector. The detector comprehended by the invention utilizes the leaky transmission line radar ranging type of detection system in which the air space over the deterrent barrier is monitored through an upward looking corner reflector antenna.